Device and method for assembling wind turbine

Abstract

The invention relates to a device (100), a system (10) and a method for modifying the cross section of a tower section (1) of a wind turbine, wherein the tower section comprises a flange (4) located at an end (3) of the tower section having a plurality of through holes (5) spaced around its circumference for securing said tower section to another wind turbine section. The method comprises securing tensioning mechanism (14) to each of a pair of said plurality of through holes in the flange of the tower section, said pair of holes being generally opposed; and applying a tensile force between said pair of holes in the flange of the tower section.

The invention claimed is: 
     
       1. A system for modifying a cross section of a tower section of a wind turbine, wherein the tower section comprises a flange located at an end of the tower section having a plurality of through holes spaced around its circumference for securing the tower section to another wind turbine section, the system comprising:
 a pair of devices, wherein each of the pair of devices comprises:
 an expandable securing member configured to be located within one of the plurality of through holes in the flange; and 
 an expansion mechanism configured to expand the securing member so as to urge the securing member into contact with the one of the plurality of through holes such that the securing member is braced against an internal wall and removal of the expanded securing member from the one of the plurality of through holes is thereby inhibited by frictional resistance between the securing member and the internal wall; 
 
 a tether configured to extend between generally opposing sides of the tower section, each end of the tether being configured to attach to a respective device of the pair of devices; and 
 a tensioning mechanism configured to couple to each of the pair of devices via the tether and further configured to apply a tensile force between the pair of devices via the tether. 
 
     
     
       2. The system of  claim 1 , wherein the securing member comprises at least first and second portions that are generally opposed, said first and second portions being arranged to come into contact with the internal wall when the securing member is expanded by the expansion mechanism. 
     
     
       3. The system of  claim 2 , wherein the securing member comprises a hollow sheath having a sheath wall, with the first and second portions of the securing member both being part of the sheath wall;
 wherein the expansion mechanism comprises a tapered member arranged to be moved axially within an open end portion of the hollow sheath; and 
 wherein the tapered member is configured such that, as the tapered member is moved into the open end portion of the hollow sheath, a tapered surface of the tapered member contacts an internal surface of the sheath wall and urges the sheath wall outwards thereby expanding the securing member. 
 
     
     
       4. The system of  claim 3 , wherein the securing member further comprises a shaft arranged to extend through the hollow sheath, the shaft comprising a threaded portion configured to engage a corresponding threaded portion of the tapered member such that rotation of one of the tapered member and the shaft relative to the other causes the tapered member to move axially along the shaft and thereby to move axially relative to the hollow sheath. 
     
     
       5. The system of  claim 3 , wherein the tapered member comprises a protrusion or cavity by which a tool may engage with the tapered member so as to apply a torque to the tapered member. 
     
     
       6. The system of  claim 1 , wherein the securing member comprises a distance measuring apparatus and/or a mount for a distance measuring apparatus. 
     
     
       7. The system of  claim 1 , wherein the tensioning mechanism comprises:
 a turnbuckle; a winch; a ratchet; a hydraulic cylinder; or a threaded rod and a threaded bracket, the threaded rod and threaded bracket being configured to engage and move axially relative to each other; 
 wherein the tether comprises two tether sections, each tether section configured to attach to one of said pair of devices and wherein the tensioning mechanism is arranged to couple the two tether sections together. 
 
     
     
       8. The system of  claim 1 , wherein the tether comprises a material having an ultimate tensile strength of at least 0.8 GPa and/or an elongation at breakage of less than 10%. 
     
     
       9. The system of  claim 8 , wherein the tether comprises a material having an ultimate tensile strength of at least 1.5 GPa. 
     
     
       10. The system of  claim 8 , wherein the tether comprises a material having an ultimate tensile strength of at least 2 GPa. 
     
     
       11. The system of  claim 8 , wherein the tether comprises a material having an elongation at breakage of less than 5%. 
     
     
       12. The system of  claim 8 , wherein the tether comprises a material having an elongation at breakage of less than 4%. 
     
     
       13. The system of  claim 1 , the system comprising a distance measuring apparatus configured to determine the distance between the pair of devices and/or between opposing portions of the tower section to which the pair of devices are secured, wherein the distance measuring device is mounted to at least one of the pair of devices. 
     
     
       14. A method for modifying the cross section of a tower section of a wind turbine, wherein the tower section comprises a flange located at an end of the tower section having a plurality of through holes spaced around its circumference for securing said tower section to another wind turbine section, the method comprising:
 providing at least one system according to  claim 1 ; 
 locating each of the pair of devices in a respective one of the plurality of through holes in the flange, the pair of the plurality of through holes in which the pair of devices are located being generally opposed to each other; 
 for each of the pair of devices, expanding the securing member using the expansion mechanism to inhibit removal of the device from its respective one of the plurality of through holes; 
 securing a tensioning mechanism to each of the pair of devices using the tether; and 
 applying a tensile force between said pair of devices using the tensioning mechanism. 
 
     
     
       15. The method of  claim 14  comprising the preceding step of:
 identifying that the plurality of through holes in the flange of the tower section is misaligned relative to a corresponding plurality of holes in the another wind turbine section to which the tower section is to be coupled; 
 wherein the tensile force is applied between the pair of devices in the flange of the tower section so as to modify the cross section of the tower section such that the plurality of through holes in the tower section are aligned with the plurality of holes in the another wind turbine section to form pairs of aligned holes between the sections tower section and the another wind turbine section; and 
 and wherein the method comprises the subsequent step of:
 fitting a bolt or stud through at least one of the pairs of aligned holes whilst the tensile force applied by the tension mechanism is maintained. 
 
 
     
     
       16. The method of  claim 15 , the method further comprising the steps of:
 removing the tensile force applied by the tension mechanism, and then removing at least one of the pair of devices from its respective one of the plurality of through holes in the flange; and 
 fitting a bolt or stud through the respective one of the plurality of through holes to which the tensioning mechanism was secured and the corresponding aligned hole in the another wind turbine section. 
 
     
     
       17. The method of  claim 14 , wherein providing the at least one system includes providing a plurality of systems, the method further comprising:
 for each system of the plurality of systems, repeating the locating, expanding, securing and applying steps; 
 wherein the tensile force from each of the plurality of systems is applied in a different direction.